[Ruiii]

Hey all, I need some help on writing UDF for heat of hydration.
I wanna to inject a fluid A into another fulid B.
I want to set a increasing temperature equation based on time to fluid A.
The equation
T=273.15K + t/2
The unit of time is seconds and temperature is K.
I am simulating an unsteady state by the way.
I didn't find any udf about the fluid heat of hydration.
I'm a complete noob so I could use some help. Thanks!

[vinerm]

As far as equation for the temperature is concerned, you do not need a UDF. You can use a transient profile. Refer

UDF for a simple sine function on base of droplet (moving wall)

Do note that the unit is s for time and K for temperature.

As far as heat of hydration is concerned, it is actually a material property. However, Fluent does not have any model for it. So, all you need to do is apply an energy source in the cell zone. Unit for energy source is . For steady-state, unit is

[Ruiii]

Originally Posted by vinerm

As far as equation for the temperature is concerned, you do not need a UDF. You can use a transient profile. Refer

UDF for a simple sine function on base of droplet (moving wall)

Do note that the unit is s for time and K for temperature.

As far as heat of hydration is concerned, it is actually a material property. However, Fluent does not have any model for it. So, all you need to do is apply an energy source in the cell zone. Unit for energy source is . For steady-state, unit is

Thank you for the reply!
But could you tell me how to use thetransient profile?
I have read the url you attached,but i am still confused.
As shown in the figure i upload , the red fluid is injected to the blue one.
You adviced to set a energy source in the fluid cell zone, wether the energy source will heat the bule fuild or not?
Or only when the red fluid flow through the cell zone , it generates heat?
Wether to use the source terms item in the cell zone condition?
Thank you for your help again!

[vinerm]

The profile is only for temperature; you can calculate temperature values for up to, say 50 or 100 seconds, and then put time and temperature values in profile file, just like vel in the profile.

For source terms, the effect is dependent upon the model being used. It appears you are using VOF. In that case, the energy source term affects all phases (all fluids). Source terms are applied always within cell zone conditions and are applied to cells not to fluids. Whichever fluid lies in that cell will receive the source. Heat of hydration is actually a reaction. But if you are not interested in modeling reaction and only in heat, then you have to use a UDF or expression to define the source term since a non-zero source value should exist only in the cells where fluids mix.

[Ruiii]

Thank you for the reply!
I will spend some time on it.

Best Regards!